1. Field of the Invention
The present invention relates generally to carrying cases and more specifically to a carrying case for protecting heat sensitive materials without the use of refrigeration.
2. Discussion of the Prior Art
There are many different methods for storing temperature sensitive materials in some type of container or enclosure. A powered cooling device which keeps the temperature sensitive item at a particular temperature may be used, except it would be impractical to carry or ship a container with a powered cooling device. A frozen liquid may be used to keep the temperature sensitive item from excess heat. However, temperature sensitive items such as cosmetics, medical supplies, or the like should be maintained at room temperature. The temperature sensitive items may be damaged if the temperature falls below their desired temperature range as the result of the introduction of excessively low temperatures. Another method utilizes a phase change material (PCM). The phase change material will absorb a large amount of energy while going through a phase change from solid to liquid.
Several patents disclose utilizing a phase change material in a rigid container. U.S. Pat. No. 4,528,439 to Marney, Jr. et al. discloses a portable thermally insulated case for use in oil and gas exploration. Oil and gas exploration occurs in hostile climates as cold as xe2x88x9240 degrees Fahrenheit (F). The phase change material is an electrically preheated mixture of water, gelatin, sodium benzoate and a biocide. When the temperature falls below 22 degrees F., the phase change material begins to freeze, thereby releasing its latent heat of fusion to the contents in the case and preventing the contents inside the case from falling below 22 degrees F. for an extended period.
U.S. Pat. No. 4,482,010 to Cordon discloses a method and apparatus for storing energy by matching a phase change material contained in the walls of a building to the average outdoor ambient temperature to maintain the interior of the building at the average outdoor temperature. U.S. Pat. No. 5,647,226 to Scaringe et al. discloses a shipping container for animal parts lined with a phase change having a phase change temperature that matches a predicted ambient shipping temperature.
However, none of these patents disclose a container that substantially matches the phase change temperature of a phase change material to the desired maximum temperature of the contents within a carrying case; nor do these patents disclose a container which may be easily sealed and unsealed to retain small items for hand carrying or insertion into a purse or the like.
Accordingly, there is a clearly felt need in the art for a carrying case for protecting heat sensitive materials which substantially matches the phase change temperature of a phase change material to the desired maximum temperature of the contents within a carrying case. Further, there is a need for a carrying case for protecting heat sensitive materials which may be easily sealed, and is compact in size.
The present invention provides a carrying case for protecting heat sensitive materials which has a compact size. A carrying case for protecting heat sensitive materials includes a first portion, a second portion, and a closure device. The closure device seals the first portion to the second portion. Each portion preferably includes a PCM retainer, insulation layer, outer fabric layer, and inner fabric enclosure. The PCM retainer is filled with a phase change material. The insulation layer is attached to an outside surface of the PCM retainer. The outer fabric layer is attached to an outside surface of the insulation layer and the inner fabric enclosure is attached to an inside surface of each PCM retainer. Preferably, the first and second portions are pivotally attached to each other by sewing a fabric hinge to a bottom of each portion. The closure device may be a zipper; a hook and loop fastener; a latch; or any other suitable closure device.
A second embodiment of a carrying case for protecting heat sensitive materials includes a cover, a container, and a closure device. The closure device seals a bottom of the cover to a top of the container. The cover preferably includes a cover PCM retainer, a cover insulation layer, a cover outer fabric layer, and a cover inner fabric layer. The cover PCM retainer is filled with a phase change material. The cover insulation layer is attached to an outside surface of the cover PCM retainer. The cover outer fabric layer is attached to an outside surface of the cover insulation layer and the cover inner fabric layer is attached to an inside surface of the cover PCM retainer.
The container preferably includes a container PCM retainer, a container insulation layer, a container outer fabric layer, and a container inner fabric layer. The container PCM retainer is filled with a phase change material. The container insulation layer is attached to an outside surface of the container retainer. The outer container fabric layer is attached to an outside surface of the container insulation layer and the inner container fabric layer is attached to an inside surface of the container PCM retainer. Preferably, the cover is pivotally attached to the container by sewing a fabric hinge to a top edge of the container fabric layer and to a portion of a bottom edge of the cover fabric layer. The closure device may be a zipper; a hook and loop fastener; a latch; or any other suitable closure device.
A third embodiment of a carrying case for protecting heat sensitive materials includes a pouch which is sealable with a closure device. The wall of the pouch preferably includes a fabric outer layer, a flexible insulating outer layer, a phase change layer, a flexible insulating inner layer, and a fabric inner layer. The phase change layer includes a first film layer, a second film layer, and phase change material heat sealed between the film layers. The phase change material is preferably heat sealed in a plurality of pockets. The closure device may be a zipper; a hook and loop fastener; or any other suitable closure device.
Accordingly, it is an object of the present invention to provide a carrying case for protecting heat sensitive materials which has flexible walls.
It is a further object of the present invention to provide a carrying case for protecting heat sensitive materials which may be easily sealed.
It is yet a further object of the present invention to provide a carrying case for protecting heat sensitive materials which substantially matches the phase change temperature of a phase change material to the desired maximum temperature of the contents within the carrying case.
Finally, it is another object of the present invention to provide a carrying case for protecting heat sensitive materials which has a compact size.
These and additional objects, advantages, features and benefits of the present invention will become apparent from the following specification.